Reenforced-concrete column



' H.. E. BUTCHER. V REENFORCED CONCRETE COLUMN. APPLICATION FILED JUNE 5,1919.

1,41 ,%3., Patented Mar. 21, 1922.

.UNHTEED STATES HERVEY E. BUTCHER, 0F BUFFALO, NEW YORK.

REENFORCED-CONCRETE COLUMN.

Appiication filed. June 5,

To all whom it may concern:

Be it known that I, HERVEY E. BUTCHER, a citizen of the United States, and a resi-' dent of the city of Buffalo, in the county of Erie and State of New York, have invented a new and useful Improvement in Vertical Reenforced-Concrete Structural Members, and Particularly in Reenforced- Concrete Columns, of'which the following is a specification.

My invention relates principally to reenforced concrete columns. Heretofore, it has been common to embed hoops or spirals in reenforced concrete columns for the purpose of taking care of the shearing or diagonal tensional stresses; but such hoops and spirals are-subject to numerous disadvantages which it is the object of the present invention to avoid. In the first place, the successive hoops or turns of the spiral are spaced apart leaving intervening spaces without circumferential reenforcement. Secondly, such hoops 0r spirals are likely to become to a greater or less extent, distorted or dislocated in the course of actual construction. Thirdly, the hoops or spirals themselves in their action in resisting the lateral pressure brou ht upon them, due to a vertical load on. t e column, become in reality cutting edges because of their intermittent concentration and thereby create shearing planes, the very thing they are intended to obviate.- Again, in the practical use of such hoops or spirals, temporary forms are required for molding the concrete. One object of the resent invention is to so design the circum erential reenforcement that it will also serve as a mold and thereby make it practicable to dispense with the temporary false work heretofore used in the erection of reenforced concrete columns. Another object is to produce a favorable keying surface on the column reenforcement for receiving a covering of fire-proofing material.

The invention consists principally in a tubular metal shell filled with concrete and designed so as to be capable of resisting the shearing or diagonal tensile stresses in the column. The metal shell may by means of slits, reticulations' or deformations, be made to form a mechanical bond with the con crete without material loss in the tensile strength of the shell circumferentially and by the same operation its exterior face be made to produce a favorable keying surface Specification of Letters Patent.

Patented Mar. 211, 11922.

1919. Serial Np. 301,862.

for receiving a covering of plastic material that w1ll serve to fire-proof the column. The nvention also consists in the process of making columns hereinafter described and claimed. It also consists in the parts and arrangements of parts hereinafter described and claimed.

In the accompanying drawing, wherein like reference numerals refer to like parts wherever they occur,

Fig. 1 is a vertical longitudinal section taken through ,a concrete column showing a tubular metal shell embodying my invent on in connection therewith, the lower porp on of the shell'being shown in side eleva- Fig. 2 is a horizontal section through the column, the section being taken through one pl f the rows ofpockets onthe line 2-2 in Fig. 3 is an enlarged face view of a portion of a fiat sheet of metal before being rolled into the form of a shell with the slits formed therein;

Fig. 4; is a section on the line 44 in Fig. 3;

Fig. 5 is a section on the line 5-5 in Fig. 3;

Fig. 6 is a vertical section taken through one of the pockets, a portion of. the concrete filling and fireproof covering being shown; and

Fig. 7 is a fragmentary horizontal section taken through the pockets adjacent to one of the.reenforcing rods showing a means for securing the rods in position.

The column comprises a tubular shell 1 of sheet metal filled with concrete 2. The-shell is provided throughout its surface with a multiplicity of slits 3, the slits being' arranged in rows and the slits in each row belng preferably staggered with res ect to the slits of the next adjacent rows. referably also, the lower lip of each slit is displaced outwardly thereby forming a kind of cup or pocket 4 which projects beyond the normal cylindrical surface of the shell. In practice, it is preferable to slit the sheet in the flat and afterwards roll it into the form of a shell and fasten its ends together eitherfiby -riveting or by lap-welding or butt-welding them. As the shell is intended to contribute tensile strength to resist the outward pressure of the concrete, it should be made in the form of acontinuous circular shell as .distinguished from a longitudinally .fluted or corrugated shell and from a sheet that is rolled into the form of a cylinder without having its ends firmly fastened together. As the joint or seam is liable to be weaker in tensile strength-than the body of the unslitted sheet, the strength of the joint or seam fixes the limit of strength of the shell; and consequently some departure from horizontality of slits is permissible. It is estimated that the joint or seam may develop about ninety-five per cent (95%) of the strength of the solid shell or of the shell with horizontal slits. This five per cent (5%) loss of efliciency would mean that the slits might be inclined with the horizontal as much as eighteen perment (18%) without injury to the tensile strength of the shell as a whole.

When the column is to have a flaring head, the upper end 5 of the reenforcing shell 1 is made of conical or pyramidal form. The upper end 5 is shown in the drawings as being made separate from the cylindrical portion of the shell and as having a tubular extension 6 at its lower end arranged to fit into the upper end of the cylindrical portion of the she I. The conical portion of the shell is made of sheet metal rolled to shape and having its ends welded or otherwise secured so as tomake the shell apable of resisting circumferential tension.

In constructing the column, the metalshell is first set in its proper position and held in place by any suitable means, the cups on the outer surface thereof being open toward the top. If vertical reenforcing rods are used, such rods 7 are properly positioned inside of the metal shell, and secured in position with reference to the shell either before the shell itself is positioned or afterwards, according to convenience. The rods 7 are preferably secured in the shell by wire loops 8 which pass around the rods and through the slits 3, small spacin blocks 10 intervening between the shell an the rods to insure the proper embedment of the rods in the concrete. When the metal shell is properly positioned, concrete in plastic or semi-plastic condition is poured into the top thereof and suitably tamped. In this way, the concrete is made to fill the entire space inside of the shell and thereby embeds the reenforcing bars. .At the same time, the concrete is caused to flow into the pockets on the outer surface of the shell and forms a mechanical bond with it. On account of the concrete being viscous, the portion that flows into a cup does not assume a horizontal level on top; but on the contrary the top thereof inclines downwardly and outwardly from the upper lip of the slit that serves to form such cup. Thus, the top of the concrete in the cup is lower than the top edge of the cup itself and consequently there is little or no loss of the concrete by leakage over the top edge of the cup. At'the same .umn in accordance with design.

time, the unfilled portion of the cup in connection with the radial projection of the wall of the cup, taken in connectionwith the multiplicity of similar arrangements through out the surface of the shell, affords an excellent bonding or ke ing surface for a fireproof covering. T is covering, preferably cement plaster, is applied in one or more layers of sufficient thickness to afford a substantially fire-proof coat 9 or protection for the column.

Heretofore, it has been impracticable for economical reasons to make reenforced concrete columns with the entasis desired for architectural effect; and it is an advantage of my invention that this desired entasis can be economically obtained.

It is noted that by reason of the mechanical bonding of the concrete core with the slitted shell, the shell is made to function as vertical reenforcement as well as circumferential reenforcement: that is to say, by reason of such mechanical bonding or interlocking of the metal shell with the concrete core, the metal materially increases the strength of the column forresisting vertical stresses as well as for resisting those circumferential stresses that have heretofore been resisted by spirals and hoops. And it is further noted that while the shell performs the functions of the hoop and spiral reenforcements heretofore used, it doesso much more efliciently by reason of the fact that the continuity of. the shell distributes the metal uniformly through the entire length of the column as compared with the intermittentconcentration of the reenforcement occasioned by the spacing of the spirals and hoops.

It is further noted that the danger of the metal shell becoming distorted or dislocated in the construction work is minimized and therefore its use assures erection of the col- It is further noted that the slitting of the shell need not reduce the capacity of the shell to resist circumferential tensile stress even though the slits are inclined with a plane at ri ht angles to the axis of the shell; provided t at the strength of the shell multiplied by the cosine of the angle of inclination of the slits is not less than the strength of the joint.

It is further noted that the use of the metal shell eliminates the necessity for the temporary form work heretofore used in the construction of reenforced concrete columns.

It is further noted that, even after the pocket forming lips of the slit are separated, they continue throughout their length at substantially the same horizontal height so that there is no such tendency for the plastic material to run out as there would be with openings wherein the upper lip is located materially above the lower lip or wherein one end-of the opening is materially lower than the other. With the limitations noted, it is obvious that the pockets may be formed otherwise than as specifically described without risk of losing any of the plastic material; for instance, the upper lip may be displaced inwardly, leaving the lower lip in its original position or displaced outwardly as desired. In such case, the inwardly projecting lip may be made to position the vertical reenforcing bars further'inwardly from the normal surface of the cylindrical shell. Obviously also there need be no slits or perforations in the shell and the slits or perforations in the shell need not be substantially horizontal to come within my invention, so long as the shell has sufiicient strength to resist the lateral pressure transmitted to it by the concrete.

What I claimv is:

1. A. column comprising a sheet of metal whose ends are brought together and firmly secured to form a shell that has a continuously convex exterior surface and is capable of resisting circumferential tension and has upwardly and outwardly opening cup shaped openings adapted toconstitute a keying surface, a filling of concrete in said shell and a fire-proofing coating surrounding said shell whereby said shell serves as a form for the concrete and as a reenforcement therefor and affords'a keying surface for the fireproofing coating.

2. A reenforced concrete column comprising a circumferentially continuous metal shell having substantially horizontal slits therein, either the upper or lower of the lips of said slits inclining so that the lower edges of the upper lips are ofi'set in-.

wardly with respect to the upper edges of the lower lips and a core of concrete interlocking with said shell.

3. A-reenforced concrete column comprising a metal shell having substantially horizontal-slits therein, the lips of said slits being integral with the shell except along the slit and the one free edge of each lip being ofi'set radially of the column with respect to the free edge of the other lip of said slit so as to form an ufpwardly opening pocket that will retain the owing concrete and provides a bonding key for a subsequent coating, a core of concrete interlocking with said shell and a coat surrounding said shell and keyed thereto.

4. A reenforced concrete column comprising a tubular metal shell and a concrete core, said shell having substantially horizontal slits therein, the lower lip of each slit being integral with the shell at its ends and base and inclining upwardly and outwardly to form a bonding pocket which will retain the flowing concrete and provide a key for a subsequent coating.

5. A reenforced concrete column comprising a tubular metal shell flaring at the end and a concrete core, said shell having horizontal slits therein and the lower lip of each slit being integral with the shell at its ends andbase and inclinin upwardly and outwardly to form a bonding pocket which will retain the flowing concrete and'provide a key for a'subsequent coating.

' 6. A reenforced concrete column comprising a circumferentially continuous metal shell, a concrete core filling and interlocking therewith, and a coating surrounding said shell, said shell having horizontally elongatedslits therein, some of the lips of said slits having an upward and outward inclination whereby the lower edges of the upper lips are positioned inwardly with respect to the upper edges of the lower lips so as to preventthe escape of flowing concrete and provide a bonding key for a subsequent coating.

7. A reenforced concrete column comprising a tubularsheet metal shell, a concrete core and vertical reenforcing rods secured in said shell, said shell having elongated horizontal slits therein, the lower edges of the upper lips of said. slits being posltioned inwardly with respect to the upper edges of the lower lips thereof to form cups which will retain the flowing concrete and form a key for a subsequent coating.

8. A reenforced concrete column comprising a tubular sheet metal shell with a flaring end, a concrete core and vertical reenforcing rods secured in said shell, said shell having elongated horizontal slits therein, each lower lip being integral with the shell 100 1 at its ends and base and inclining upwardly and outwardly to form a pocket which will retain the flowing concrete and form a bonding key for a subsequent coating.

9. A combined, form and reenforcing 105 member for concrete columns, comprisin a tubular metal shell having horizontal sits therein, the lower edges of the upper lips of said slits being positioned inwardly with respect to the upper edges of the lower lips 11 thereof so as to form cups which will retain the flowing concrete and form a key for a subsequent coating.

10. A combined form and reenforcing member for concrete columns, comprising a 1 circumferentially continuous metal shell flaring at the end and having horizontal slits therein, the lower edges of the upper lips of said slits being positioned inwardly with respect to the upper edges of the lower lips 1% thereof.

11. A combined form and reenforcing member for a concrete column, comprising a circumferentially continuous tubular metal shell having horizontal slits therein, the. 125

- lower edges of the upper lips of said slits gg being positioned inwardly with respect to-'; the upper edges of the lower lips thereof and metal rods secured lengthwise in said shell.

12. The process of making columns which no consists in rolling a sheet of metal into cylindrical form, securing the edges thereof together to form a circumferentially continuous shell capable of resisting circumferential tension, erecting said shell in position, mounting thereon an inverted conical shell adapted to resist circumferential tension, filling said cylindrical and conical shells with concrete and coating the same with fireproofing material. i

13. The process of making columns which consists in rolling a sheet of metal into cylindrical form, securing the edges thereof together to form acircumferentially continuous shell capable of resisting circumferential tension, erecting said shell in position, placing vertical reenforcing bars therein, mounting thereon an inverted conical shell adapted to resist circumferential tension, filling said cylindrical and conical shells with concrete and foating the same with fireproofing materia 14. The process of making a combined form and reenforcing member for concrete columns which consists in slitting a sheet of metal and rolling it into the form of a shell and joining the ends of said sheet together to form a circumferentially continuous shell, the slits being so designed and disposed that the slitted portion of said shell will be ca.- pable of resisting at least as much circumferential tension as said oint.

15. A combined form and reenforcing member for concrete columns, comprising a sheet of metal rolled into a circumferentially continuous tubular shell having a longitudinal seam, said shell having slits therein, said slits being so disposed that the circumferential tensile strength of the slitted shell is substantially equal to the tensile strength of the seam.

Si ned atBufialo, New York, this 31st day of ay, 1919.

HERVEY E. BUTCHER. 

